Separation filter's in general
Several concepts, products, manufactures exist for upstream separation purposes. The use of different expressions is huge and in general serving the same purpose:
Tangential-Flow-Filtration (TFF) involves the recirculation of the retentate along the surface of the membrane. This gentle cross flow feed acts to minimize membrane fouling, maintain a high filtration rate and provide higher product recovery.
Cross-Flow-Filter (CFF) is a device which allow selectable components under some pressure to pass from one liquid volume into another liquid volume crossing a “membrane” eliminating other components to pass the membrane.
Hollow-Fiber-Filter (HFF) modules is based on a number of parallel arranged extruded straw arranged inside a transparent plastic tube. The active pore size is well controlled ranging from Dalton to few microns.
An important parameter is the Trans-Membrane-Pressure (TMP) - the force that drives liquid through the membrane. During filtration, the feed side of the membrane is under pressure higher than the permeate side. This pressure difference forces liquid and the desired particles through the membrane.